johninar

I've been getting a lot of email and IMs asking how hard is it, instructions, pictures etc. Here are some photos I took while doing my seat. Many thanks to Meldog. Without his help it might not have been as easy.

First step is to remove the seat. Easy enough, remove the front covers and then the 4 nuts holding the seat in. I then prop the front up to give me room to unhook the power seat connector on the drivers side.

Find the end of the zipper that is tucked up in the back. I attach a zip tie to make working the zipper easier. You will be putting the seat cover on several times during this process.



Remove the seat release clip



Front view with cover off



Rear view showing the seat frame.


Mark the center location using an ice pick or similar tool.


Not a lot of choice for grommet location. Putting the grommets in backwards allows the lip to hold it in place for measuring.



Mark the grommet locations with a felt tip pen.


Hold your breath and grab the carving knife!
Please note the knife blade will need to be cleaned with rubbing alcohol often! You will feel the knife drag on the foam when it needs to be cleaned.




Both grommets installed from rear.


After installing the grommets, replace the seat cover. Pressing on the vinyl you can feel where the seat grommets are positioned. After ensuring that you are happy with the grommet locations, you can cut a slot crossways. Then two small cuts from the center up toward each corner. Your cut should look like this

>----<

Remove the seat cover and the seat grommets. Replace the seat cover and install the grommets. If everything looks good, use some glue to keep the front and rear grommets securely together.


Finished product.

UstaB-GS549

Nice write-up!

FredSM

Very nice write-up and pics. Thank you!!!

FM

dvandentop

where did you buy the grommets at?

Dreamin

Nice!

BrianCunningham

I've always liked my stock seats, and may have a go at doing that.

johninar

I got my seat grommets from here http://www.hmsmotorsport.com/store/z...arnesses/#2205

$15.00 each, you will need 4 to do both seats.

Wayne O

Nice write up and good job!

I did something very similar with my seats. It works well.

dvandentop

thanks for the link + doesnt defeat the comfort of the stock seats

RUN4CVR

Nice...a good alternative to switching to race seats and losing all the airbag protection I assume?

Gary2KC5

Not sure what protection the air bags would do but you are correct you do lose them. If your in trouble enough to ignite the air bags that initial hit will probably not be your only one.

waddisme

Does this set up with a 5 or 6 point harness help keep your butt in the seat or is it just for crash protection? I am ready to upgrade my seat, but I was just going to get something I could switch out for track days as I dd my car. This seems like a good compromise if it helps keep butt stable. It physically wears me out by the end of the day having to use steering wheel and speaker grill to stay in seat. Let me know. Thanks.

AlwaysInBoost

nice diy!

Foxer55

Are these seats "legal" on all tracks? I seem to remember seeing somewhere they are not acceptable on some tracks.

I'm looking at an option like this because, while I believe true race seats are a good thing, they are crappy looking in my spiffy Corvette that I want to make a dual show and track car which these seats certainly do.

jcsperson

I have the sport seats so I don't need this, but would like to put a slot on the bottom of the seat for the fifth belt on my harness.

Gotta DIY for that?

geerookie

This is NOT legal for any santioning body. This is only for looks and provides no safety improvements. I would go as far to say it makes things much worse if you are wearing a harness and were in a crash!
And if you went through my tech line you wouldn't even be allowed out for a lead follow session wearing that let alone HPDE or racing.

An approved race seat supports the harness above your shoulders and when the impact throws you forward the race seat supports the shoulder belts and keeps them from compressing your spine!

When a shoulder harness is properly installed the rear attachment point is below the top of your shoulders. This is to keep the belts from sliding off the sides of your shoulders. Since it is lower if the seat back didn't support the harness as you move forward the belts will move down in this type of application and compress your spine.
Go to Schroth's website and study about how a 6 point harness works and is installed properly.
This mod is dangerous.

geerookie

Again, not legal in any santioning body.
Race harness mean race seats.

jcsperson

Even for HPDE?

Bill Dearborn

It isn't a matter of the track ruling what is required but what the various groups/clubs running the events state what is required. Here is a link to a BMW Club Tech Form: http://www.gvc-bmwcca.org/_download/...ch_Medical.pdf They also do not allow modifying the seat to put holes in it for shoulder harnesses. HMS Motorsports provides technical assistance to them in this area and even though they sell the grommets referenced in this thread you will be told you can't use such a seat in these events. There are a lot of reasons this is so since the belts rarely can be installed the way the manufacturers say to install them. One of the big issues of even using the C5 sport seats is the hole in the seat isn't placed well to allow a straight path from the shoulder belt mounting point across the top of your shoulders. If the seat doesn't permit this at the proper angle for the belt the seat back becomes a fragile piece of the harness system which will break under the heavy load of a crash allowing the belt to go straight thus creating slack and letting you fly forward or sideways.

As for running the sub belt out through the bottom of the seat you need to modify the seat spring to do that. This is what they look like on both the C5 and C6 (picture of C5 seat)



Cutting the center springs to make room for two sub belts will take quite a bit of the support away from the center of the seat. A while ago C5 drivers used to disconnect the springs so they dropped lower in the seat but then they had problems with the recline mechanism and other things that weren't supposed to have that much pressure on the. If you cut the springs you need to make sure the left over ends aren't going to damage the sub belts during use or when the seat is being moved. If you are using a power seat or a C6Z seat that has seat heaters and a passenger presence system there are a lot of things below the seat that can interfere with or be damaged by the sub belts.

Bill

jcsperson

Hmmnnn....

Looks like race seats might be in order some day....